The present invention relates to a liquid crystal display device, and more particularly to an effective technique for driving circuits of a liquid crystal display device used in a portable display device.
Liquid crystal display devices adopting a STN (Super Twisted Nematic) method or a TFT (Thin Film Transistor) method have been widely used as display devices of notebook type personal computers or the like. The liquid crystal display device includes a liquid crystal display panel and driving circuits which drive the liquid crystal display panel.
Among these liquid crystal display devices, the liquid crystal display devices which are used as display devices of portable terminal equipment such as portable telephones are increasing in number. In adopting the liquid crystal display device as the display device of the portable terminal equipment, a liquid crystal display device which is further miniaturized and exhibits smaller power consumption than a conventional liquid crystal display device has been requested.
As a drawback which is brought about by the miniaturization of the portable terminal equipment, the reduction of space for mounting driving circuits of the liquid crystal display device has been pointed out. There is a demand for a so-called centering of screen which is a method characterized by aligning the center line of the portable terminal display device with the center of a display screen. However, in meeting such a demand, positions where driving circuits can be mounted are restricted and much consideration is necessary to determine the arrangement of the driving circuits. Further, although the driving circuits are mounted on two neighboring sides of the display screen in the conventional liquid crystal display device, there is a demand for a so-called three-side-free arrangement which mounts the driving circuits on only one side. Further, there is a demand for the reduction of the number of mounting parts in order to miniaturize the mounting area.
The present invention has been made to solve the above-mentioned drawbacks of the prior art and it is an object of the present invention to provide a technique which can realize optimum driving circuits in a miniaturized liquid crystal display device.
The above-mentioned object, other objects and novel features of the present invention will be made apparent by the description of this specification and attached drawings.